I would try the Strelitzias, very tropical looking but apparently quite cold hardy and very resiliant. Also Hedychium gingers die down in winter so they dont get affected by frosts. Look into the frost tolerant palm species, they are what really helps create a tropical looking garden.

You might also want to look at the "tropicalesque" forum on the US tropical page.

hope this is helpful.

The first thing I would recommend is geting a windbreak growing. If you can protect the area from the strong cold wind there is a good range of interesting plant that will grow. I drop to around -2C every year or so and regularly spend months during the winter with 0C to 5C nights, but without frosts. The secret is to create a micro climate and your strong wind is going to interfere with that. Many of the Hedychiums will grow and flower in even heavy frost areas, but the wind will blow them over. Some of the deciduous gingers are proving very cold tolerant in the USA. They must be kept dry during the winter while dormant. They are easy in a pot until you are sure about position. Some species I've over wintered in pots are
Zingiber collinsi cv 'Silver Streaks', Zingiber niveum cv MilkyWay, Cornukaempferia aurantifolia cv 'Velvet Butterfly, Kaempferia pulchra, Globba globulifera cv Mauve Bells, Globba winitii, Globba copicola. Remember to keep the pots on the dry side until they Break dormancy. If you are planting them a raised bed is vital if you get the winter rain that happens on the east coast nsw.

I haven't had much luck with the Curcumas. Still learning about them. Mine don't break dormancy early enough to get good flowers and a few people have said the same thing. I think it's just culture and I need to learn to grow them better.

By the way I just had a heatwave with a peak of 46.5C in the shade. The next day it was 18C, I Just love summer in NSW.

Hope this is helpful.

Rob